First application of a digital mirror Langmuir probe for real-time plasma diagnosis

McCarthy, W.; Golfinopoulos, T.; Woller, K. B.; Vincent, C.; Kuang, A.; Labombard, B.

doi:10.7910/DVN/BRJE87

Title: First application of a digital mirror Langmuir probe for real-time plasma diagnosis

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Abstract

For the first time, a digital Mirror Langmuir probe (MLP) has successfully sampled plasma temperature, ion saturation current, and floating potential together on a single probe tip in real time in a radio-frequency driven helicon linear plasma device. This is accomplished by feedback control of the bias sweep to ensure a good fit to I-V characteristics with a high frequency, high power digital amplifier and field-programmable gate array (FPGA) controller. Measurements taken by the MLP were validated by a low speed I-V characteristic manually collected during static plasma conditions. Plasma fluctuations, induced by varying the axial magnetic field (f̃ = 10 Hz), were also successfully monitored with the MLP. Further refinement of the digital MLP pushes it towards a turn-key system that minimizes the time to deployment and lessens the learning curve, positioning the digital MLP as a capable diagnostic for the study of low radio-frequency plasma physics. These demonstrations bolster confidence in fielding such digital MLP diagnostics in magnetic confinement experiments with high spatial and adequate temporal resolution such as edge plasma, scrape-off layer, and divertor probes.

Authors:

McCarthy, W.; Golfinopoulos, T.; Woller, K. B.; Vincent, C.; Kuang, A.; Labombard, B.

OSTI

Publication Date:: Wed Mar 02 04:00:00 UTC 2022

DOE Contract Number:: SC0014264

Research Org.:: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

OSTI Identifier:: 1887789

DOI:: https://doi.org/10.7910/DVN/BRJE87

Citation Formats


                    McCarthy, W., Golfinopoulos, T., Woller, K. B., Vincent, C., Kuang, A., and Labombard, B. First application of a digital mirror Langmuir probe for real-time plasma diagnosis.  United States: N. p., 2022. 
        Web.  doi:10.7910/DVN/BRJE87.

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                    McCarthy, W., Golfinopoulos, T., Woller, K. B., Vincent, C., Kuang, A., & Labombard, B. First application of a digital mirror Langmuir probe for real-time plasma diagnosis.  United States.  doi:https://doi.org/10.7910/DVN/BRJE87

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                    McCarthy, W., Golfinopoulos, T., Woller, K. B., Vincent, C., Kuang, A., and Labombard, B. 2022.  
"First application of a digital mirror Langmuir probe for real-time plasma diagnosis".  United States.  doi:https://doi.org/10.7910/DVN/BRJE87.  https://www.osti.gov/servlets/purl/1887789. Pub date:Wed Mar 02 04:00:00 UTC 2022

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@article{osti_1887789,

  title        = {First application of a digital mirror Langmuir probe for real-time plasma diagnosis},

  author       = {McCarthy, W. and Golfinopoulos, T. and Woller, K. B. and Vincent, C. and Kuang, A. and Labombard, B.},

  abstractNote = {For the first time, a digital Mirror Langmuir probe (MLP) has successfully sampled plasma temperature, ion saturation current, and floating potential together on a single probe tip in real time in a radio-frequency driven helicon linear plasma device. This is accomplished by feedback control of the bias sweep to ensure a good fit to I-V characteristics with a high frequency, high power digital amplifier and field-programmable gate array (FPGA) controller. Measurements taken by the MLP were validated by a low speed I-V characteristic manually collected during static plasma conditions. Plasma fluctuations, induced by varying the axial magnetic field (f̃ = 10 Hz), were also successfully monitored with the MLP. Further refinement of the digital MLP pushes it towards a turn-key system that minimizes the time to deployment and lessens the learning curve, positioning the digital MLP as a capable diagnostic for the study of low radio-frequency plasma physics. These demonstrations bolster confidence in fielding such digital MLP diagnostics in magnetic confinement experiments with high spatial and adequate temporal resolution such as edge plasma, scrape-off layer, and divertor probes.},

  doi          = {10.7910/DVN/BRJE87},

  journal      = {},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Wed Mar 02 04:00:00 UTC 2022},

  month        = {Wed Mar 02 04:00:00 UTC 2022}

}

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DOI: https://doi.org/10.7910/DVN/BRJE87

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